This invention relates to monitoring and annunciating systems and, more particularly, to such systems used to monitor the operation of an internal combustion engine, such as a diesel engine or the like, and to annunciate which of a plurality of monitored operating parameters or conditions has caused engine shut down.
Although the invention will be described in detail below with reference to a monitoring and annunciating system used in conjunction with a conventional diesel engine, such as a diesel engine that is used to power refrigeration equipment in a railroad refrigerator car, it is to be understood that the invention may be used in conjunction with other types of devices that have plural operating parameters of which it is desirable to effect monitoring and to indicate for a relatively long period of time the first operating parameter that fails and causes shut down of the device, especially when the device is remotely located and/or not subject to relatively frequent supervision. The instant invention, therefore, provides to an observer an indication of the first occurring fault that has caused the shut down of a monitored engine or similar device.
One prior art annunciator and control system is described in U.S. Pat. No. 3,512,405. The system of such patent includes respective logic indicating circuits directly coupled to parameter sensitive switches of a diesel engine to indicate occurrence of a shut down causing fault, and a disable circuit ensures that only the first occurring fault is indicated. A centrifugal switch in the engine closes when the engine comes up to speed, after which a timer delays the indication of a fault, for example, caused by the opening of a switch in response to low oil pressure, until the engine has been running sufficiently long for the oil to come up to proper operating pressure.